<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head>
    <title>CSS Test Reference</title>
  </head>
  <body>
    <div style="width: 100px; border: 1px solid green;">
      <div style="display: block; height: 20px; width: 80px; margin: 10px 0 10px 10px; border: 5px solid black"></div>
    </div>
  

</body></html>